How to Recognize Poison Ivy, Oak, or Sumac

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How to Recognize Poison Ivy, Oak, or Sumac

Topic Overview

Poison ivy, oak, and sumac are found throughout Canada. Poison oak is rare in Canada.

See a picture of poison ivy, oak, and sumac.

The plants may look different depending on the season and the area where they are growing. But all of these plants have small white, tan, cream, or yellow berries in the fall. Their berries can help distinguish them from harmless but similar plants.

After the leaves have fallen off, these plants can sometimes be identified by the black colour on areas where the oil in the plant (urushiol) has been exposed to air.

Poison ivy

Poison ivy is found in every province except Newfoundland. It is more common in southern Ontario and Quebec.

Poison ivy:

  • Usually has three broad, spoon-shaped leaves or leaflets, but it can have more. The phrase, "Leaves of three? Let it be." may help you remember what poison ivy looks like.
  • Grows as a climbing vine or a low, spreading vine that sprawls through grass (more common in southeastern Canada) or as a shrub (more common throughout Canada, especially in the Great Lakes region).
  • Often grows along rivers, lake fronts, and ocean beaches.
  • Has bright red leaves and white or cream berries in the autumn.

Poison oak

Poison oak is rare in Canada, but it can be found in remote areas on the east coast of Vancouver Island and some nearby islands..

Poison oak:

  • Has leaves that look like oak leaves, usually three leaflets but sometimes up to seven per leaf group.
  • Grows as a vine or a shrub.

Poison sumac

Poison sumac is much less common than poison ivy. It is found in wooded, swampy areas, such as southern Ontario and southern Quebec. It is also found in wet, wooded areas in the northern United States, and in wooded, swampy areas in Florida and other southeastern states.

Poison sumac:

  • Has 7 to 13 leaflets per leaf stem. The leaves have smooth edges and pointed tips.
  • Grows as a shrub or small tree.

Where they are not found

  • None of these plants grow well above 1219 m (3999 ft), so the higher elevations in places such as the Rocky Mountains, the St. Elias Mountains, and the Coastal Mountains are relatively free of them.
  • None of these plants grow well in deserts, except along the banks of rivers, streams, and ponds. But heavy rainfall can make a dormant plant grow again, even in a desert.
  • Hawaii does not have any of these plants, although other plants that cause a skin rash are found on the islands. For example, mango trees grow in Hawaii, and the skin of mangoes contains the same allergenic oil (urushiol) as these plants.
  • These plants do not grow in the Yukon, Nunavut, or Northwest Territories.

Related Information

Credits

By Healthwise Staff
Primary Medical Reviewer William H. Blahd, Jr., MD, FACEP - Emergency Medicine
Primary Medical Reviewer Anne C. Poinier, MD - Internal Medicine
Specialist Medical Reviewer H. Michael O'Connor, MD - Emergency Medicine
Last Revised October 22, 2009

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